Replicon-based expression vectors have been developed for various RNA virus families, including alphaviruses, picornaviruses and flaviviruses. For example, expression system utilizing Yellow Fever viruses (YFV) for the presentation of foreign proteins or polypeptides that act as immunogens or therapeutic agents in host cells are well known. However, expression of foreign proteins or polypeptides in the prior art expression systems or vectors is limited to the structural regions of the flaviviruses.
The present invention overcomes the disadvantages and defects of the prior expression systems or vectors in that it provides the ability for foreign proteins or polypeptides to be functionally expressed in the nonstructural region of the virus, particularly, the C-terminus of a secreted non-structure protein 1 of a flavivirus.